Apparatus for measuring gas-pressures.



PATENTED JAN. 15, 1907:

P. .DE BRUYN. APPARATUS FOR MEASURING GAS PRESSURES.

APPLICATION FILED NOV26.1906.

m w a ,n'srrnr sTAfrEs ATENT tron S ecification of Letters ,Patent.

Application fil d November 26,1906. Serial No. 345,154.

- To ail whom it may cncerm- Be it known that 1, PAUL nn BRUYN, subject of the German Emperor, residing at Dusseldorf, Germany, have invented new and useful Improvements in Ap aratus for Measuring Gas-Pressures, of which the following is a specification.

Apparatus for measuring gas-pressures comprising a rod or rods forming part of the mechanism extending to the outside of the apparatus through a liquid seal of the bell type are liable to give erroneous indications, the amount of error varying'with the fluctuating gas-pressure acting upon the inside of the seal-bell. 'This error, which is not so important in the case of ordinary simple or direct measurements, becomes of very great im-' portance in the case of diiferential-pressure measurements and scientific observations.

This inventionhas now for object to obviate completely this liability to error by the provision of the improved li uid seal which is hereinafter described, and ilustrated in the accompanying drawings, in Which- Figure 1 is a vertical central longitudinal section. Fig. 2 is a plan of a practical construction of the improved apparatus.

a is a measuring vessel or pressure-chamber containing a bell or float b of any suitable kind, which varies its position under the iii-- fiuence of the gases admitted through the inlets c and d. The movement of the float is transmitted by means of the rod f tothe pointer g.

For the purpose of sealing the space h from the atmosphere there is employed a liquid seal of the ordinary bell type consisting of two tubes "L and is, mounted one within the other on the cover of the chamber a. In the space between these two tubes is liquid into which dips a cylindrical bell Z, open at its lower end, that is attached to and surrounds the red It is obvious that in this arrangement the bell Z is caused by the varying gaspressure in the space m below it to exert an influence upon the movement of the rod f which will aflcct the indications of pressure to an extent that will be the greater the greater the fluctuations of pressure which are transmitted through the inlet d and the smaller the difference between the pressures at the inlets c and (1. New in order to obviate this undcsirable influence by means of a counteracting influence the bell Z is connected, according to this invention,to the bell Z of another similar liquid seal cross-sectional area and communicating with the same pressure-chamber in such a manner that the gas-pressures acting upon the two bells will counteract each other. A simple means of carrying out this idea is to provide a two-armed lever g 9 fulcrumed on a support between the two bells, the arms 9 and g eing pivoted to the bells l and Z, respectively. f

The arm g may be extended, as shown, to constitute a part of the pointer g, whichindicates the pressure or the difference between the pressures;v When certain circumstances bell l of the second liquid seal i reclude the from hav- Patented Jan. 15,1907.

ing the same internal cross-sectional area as the bell Z, then the lengths of the arms of the lever g 2 must beto each other in the inverse proportions'ofthe respective cross-sectional areas.

In cases where special circumstances do not allow of the arrangement of thesecond seal over the chamber with which the first seal is in communication or where a second chamber is available in which there is a pres-,

sure varying proportionally with the pressure in the first chamber the second seal msay be applied to the said second chamber.

is to be understood that the cross-sectional areas of the bells and the lengths of the levers on which they act must be suited to the 'pressureor pressure difierences.

This invention is also applicable with advantage in cases Where only the gas pressure under the hell I) is to be measured or where the space above the said bellis a closedspace-' that is to say, must not be in communication with the atmosphere. In such cases the movement of the bell causes a variation in the pressure in the space above it, which will give rise to errors of measurement. These errors will be obviated by the use of the second or counter seal-i according to this invention.

I claim 1. In apparatus for measuring gas-pressures in which a rod is employed to transmit the measuring movement from within a pressure-chamberto an external indicating de- ;Vice, the combination with said pressurechamber, of a liquid seal of the bell type for sealing the said rod, an idle similar liquid seal communicating with said pressure- I chamber, and a lever connecting the bells of the two liquid seals one with the other,

having the same whereby the upward tendency of the bell of theidle seal will exactly counteract the upward tendency of the bell of the rod-seal, and thereby the error in the measurement due to the bell of the said rod-seal is obviated, as set forth.

2. In apparatus for measuring gas-pres sures in which a rod is employed to transmit the measuring movement from within a pressure-chamber to an external indicating device, the combination with said pressureehamber, of a li uid seal of the bell type for sealing the saic rod, a separate pressurechamber in which the pressure corresponds to the pressure in the first-mentioned pressure-chamber, an idle li( uid seal of the bell type communicating wit said separate prese sure-chamber, and a lever connecting the bells of the two liquid seals one with the other, whereby the upward tendency of the bell of the idle seal will exactly counteract the upward tendency of the bell of the rodseal, and thereby the error in the measurement due to the bell of the said rod-seal is obviated, as set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

PAUL DE BRUYN.

Witnesses ALFRED POHLMEYER. M. ENGELS. 

